This study examines the interactions between the IGF's, the IGF-BP's, nutrition and growth in young children with both normal and aberrant growth. Concentration of IGF's and IGF-BP's in cord blood from cohorts of AGA and SGA newborns are being correlated with birthweight and other anthropometric indices. A longitudinal study examines these same indices along with IGF and IGF-BP serum concentrations, nutritional intake and body composition among cohorts of AGA and SGA infants from age 2 weeks to age 3 years.